1. Field of the Invention
This invention relates to line tensioning systems and, more particularly, to a hydraulic fluid system for providing regenerative braking and cable tensioning in a yarder cable hauling device.
2. Description of the Prior Art
Hydraulic regenerative braking systems for cable hauling apparatus are known in the prior art. For example, U.S. Pat. No. 3,346,237 to Erickson discloses a logging yarder having a system for hydraulically braking one cable drum of a yarder while providing supplemental driving force to the other drum including a pair of variable displacement motors mechanically connected with the main line drum and the haulback drum, respectively. While each of the variable displacement motors are said to be convertible to a fixed displacement unit, the Erickson patent fails to disclose means for maintaining a pre-determined selectable tension in the cable while also providing regenerative braking, or means for tensioning the cable when the yarder power source is not driving the cable drums.